Production of artificial filaments, films, and like products from viscose



Patented Got. 20, 1936 STATES PATENT OFFICE PRODUCTION OF ARTIFICIAL FILAMENTS,

FILMS, AND LIKE PRODUCTS FROM VIS- COSE Henry Dreyfus, London, England 10 Claims.

This invention is a divisional application of application S. No. 488,830 filed th October, 1930 and relates to the production of filaments, yarns, threads, ribbons, films and other products from viscose.

According to the present invention filaments, threads, ribbons and other products are produced from solutions of viscose by coagulating the viscose in the form of a cellulose xanthate of a metal other than that originally combined in the viscose and continuously treating the formed products to regenerate the cellulose. Preferably the regeneration of the cellulose is effected by treating the formed products with strong acids, for example strong mineral acids or acid esters thereof or organo mineral acids. By means of the present invention products are obtainable of fine denier or small cross-section and of high strength.

Thus the viscose may be coagulated by extruding its solution into an aqueous solution of a salt of a suitable metal, for example a heavy metal salt.

As indicated above, the conversion of the metallic cellulose xanthate into regenerated cellulose is preferably efiected by treatment with strong solutions of mineral acids, of acid esters thereof or of organo-mineral acids. For instance the conversion bath may consist of an aqueous sulphuric acid of 45% strength or higher up to 85% or more, or may consist of an aqueous solution of another mineral acid or of an acid ester of a mineral acid of equivalent concentration, for example an aqueous hydrochloric acid of to 40% concentration, or of an aqueous solution of nitric acid of 50 to 80% strength or more, or of an aqueous phosphoric acid of 60% strength or above. Again concentrated organo-mineral acids may be employed, for example sulphonic acids (compare my U. S. application S. No. 450,872 filed 8th May, 1930). The term organomineral acids is used as denoting the derivatives theoretically obtainable by replacing one or more hydroxy groups of a dior poly-basic mineral acid with one or more aryl, alkyl, aralkyl or other organic radicles, one or more hydroxy groups still remaining therein. Examples of such organo-mineral acids are methyl sulphonic acid, ethylene sulphonic acid, propyl di-sulphonic acids, sulpho-acetic or succinic acid, ethanol sulphonic acid, benzyl sulphonic acid, benzene, phenol, naphthalene and naphthol mono-, diand poly-sulphonic acids, sulpho-salicyclic or sulpho-phthalic acid.

If necessary or desirable additions may be made to the baths containing the acids, for example an addition of glycerine, glucose or other sugars, alcohols or sulphonated oils. Such additions preferably have no action on the acid constituents of the bath. Again if desired such additions may be made to the coagulating baths.

A stretch may be applied to the filaments or other products at any desired stage during or subsequent to their production. If desired a stretch may be applied to the products during their initial coagulation, but preferably a stretch is only applied thereto after coagulation and during or after conversion. Suitable resistances, such as rods, rollers or the like, may be employed between the coagulating bath and the conversion bath to prevent the stretch or tension extending back to the spinning or extrusion nozzles where this is desired.

The use of metallic salts other than alkali metal salts in the coagulation is of advantage according to the present invention in that the presence of these metals in the formed filaments, threads or other products may be utilized for the formation therein of white or coloured insoluble metallic salts. For example, if the coagulation be effected by means of an aqueous.

solution containing a barium salt, upon carrying the coagulated products into sulphuric acid, a simultaneous conversion of the xanthate into regenerated celelulose and of the barium into white insoluble barium sulphate takes place, and opaque more or less non-lustrous products are produced. Similarly by suitable choice of metallic radicle, coloured salts may be precipitated in the filaments or other products. In some cases it may be desirable to efiect the precipitation of the metallic radicle in insoluble form after the regeneration of the cellulose. Again, if the mineral acids or organo-mineral acids employed as regenerating agents are not suitable for the precipitation of the metals in insoluble form, additions may be made thereto for this purpose.

The invention, though preferably involving the use of strong mineral acids or organo-mineral acids for the conversion, is not limited thereto. Any suitable reagents, for example, dilute acids, salts or other reagents known in the viscose art for simultaneous coagulation and conversion, may be employed.

The following example illustrates the invention but is not to be considered as limiting it in any way:-

Example A normal viscose spinning solution is extruded through 0.06-0.12 mm. nozzles into a coagulating bath consisting of a 10% aqueous solution of barium chloride and the filaments are carried round a feed roller, with or without stretching, and directly into a conversion bath of aqueous sulphuric acid. The bath may contain the acid in a relatively low concentration such as 10-20% or a high concentration such as 60-80%, in which latter case it is preferably maintained at low temof aqueous sulphuric acid aqueous benzene sulphonic acid, for instance in 6.0% concentration,

may be employed.

What I claim and desire to secure tyilears' Patent is:

1. Process for the production of spun products from viscose, which comprises extruding viscose solutions in the required shape into a -coagulating medium, free from mineral acidity,

containing in solution a compound of a metal yielding by reaction with the viscose an insoluble cellulose xanthate and capable of yielding a" pigment-like compound, and treating the formed products on emergence from the coagulating medium with a regenerating bath containing an agent capable of forming said pigment-like compound. l 1" 2. Process for the production of spun products from viscose, which comprises extruding viscose solution into a coagulating medium, free from mineral'acidity, containing in solution a barium salt, and continuously treating the'formed products with an agent capable of regenerating the cellulose and of forming awhite insoluble barium compound therein.

3. Process for the production of spun prod-' ucts fro-m viscose, which comprises extruding viscose solutions into a coagulating medium adapted to precipitate the viscose in theform of a xanthate of a metal diiferent from that originally present in the viscose, and treating the formed products after emergence from-the coagulating medium with a regenerating medium comprising a substance capableof forming-an insoluble compound of the said metal.

4. Process for the production of spun prod ucts from viscose, which comprises extruding viscose solutions into a coagulating medium adapted to precipitate the viscose in the form of a xanthate of a metal difierent from that originally present in the viscose, and treating the formed products after emergence from the coagulating medium with an acid regenerating medium comprising a substance capable of forming an insoluble compound of the said metal.

5. Process according to claim 3, in which the regenerating medium comprises a mineral acid.

6. Process according to claim 3 in which the regenerating medium comprises an acid ester of a mineral acid.

7. Process according to claim 3 in which the regenerating medium comprises an organo-mineral acid.

8. Process for'the production of spun products from viscose, which comprises extruding viscose solutions into a coagulating medium adapted to precipitate the viscose in the form of the xanthate of a metal different from that originally present in the viscose and which forms an insoluble compound by reaction'with sulphuric acid, and'treating the formed products after emergence from said coagulating medium with an aqueous solution of said sulphuric acid to regenerate the cellulose.

9. Process for the production of spun prodfi ucts from viscose, which comprises extruding viscose solutions into a coagulating medium adapted to precipitate the viscose in the form of barium cellulose xanthate, and treating the formed products after emergence from such coagulating medium with sulphuric acid. a

10. Process for the production of spun products from viscose, which comprises extruding viscose solutions in the required shape into a 00-. agulating medium containing barium chloride and continuously treating the formed products with aqueous sulphuric acid.

HENRY DREYFUS. 

